Firstly, the 'aaahs' and Paul's section seem to be on the one take. You can hear him take a deep breath right before it. Plus, although the tone of the voice does have a Lennon-type presence, it's very much kept in tune, something which Lennon wasn't great at with the higher notes (see I Am The Walrus). Basically, it has more aspects of a traditional vocalist, rather than that of a snarling, raw Lennon.

A think that may settle it there - he misses his cue and then says ohhhh sh*t in its place ? ive always thought it sounds like Paul and similiat his voice he sings in on Coming up almost chipmunky sounding

Just joined, so forgive me if I've missed some previous arguments. However, I think the whole matter was answered in Geoff Emerick's book, "Here, There and Everywhere." On page 152 he goes into some detail about preventing a potential overdub problem at the "...dream/aaahh" point. He's very clear that immediately after Paul's "....went into a dream" John begins his "aaahhh." Emereick's credibility is solid and he was in a position to know what was going on with this song.

Just joined, so forgive me if I've missed some previous arguments. However, I think the whole matter was answered in Geoff Emerick's book, "Here, There and Everywhere." On page 152 he goes into some detail about preventing a potential overdub problem at the "...dream/aaahh" point. He's very clear that immediately after Paul's "....went into a dream" John begins his "aaahhh." Emereick's credibility is solid and he was in a position to know what was going on with this song.